The invention relates to an occupant protection device for a motor vehicle having at least one inflatable airbag.
In the case of a generic occupant protection device for a motor vehicle, as described in Canadian Patent Application No. 2,106,347, use is made of an inflatable airbag which, upon activation of at least one associated gas generator, leaves an exit opening in the region in front of an occupant and enters the interior of the motor vehicle. This airbag contains two chambers, a lower thorax-protection gas chamber being inflatable by the gas generator. Arranged above the thorax-protection gas chamber, with a common intermediate wall, is a head-protection gas chamber, the intermediate wall being provided with gas-throughflow openings, through which the head-protection gas chamber can be inflated via the thorax-protection gas chamber.
Following the activation of the gas chamber, a gas jet is directed straight at the occupant, so that, immediately after leaving the exit opening, the airbag shoots towards the occupant with undesirably vigorous aggressiveness before the thorax-protection gas chamber unfolds and the head-protection gas chamber is then also inflated via the gas-throughflow openings. The completely inflated airbag has a balloon-like shape, so that there is a bead-like bulge also in the region where impact is made with the neck. As a result, it is not possible to rule out the possibility of the airbag moving under the chin of the occupant, in particular at its connection between the thorax-protection gas chamber and the head-protection gas chamber directed at the occupant, and of the head of the occupant then being accelerated backwards, counter to the direction of impact, with severe stressing of the cervical spine.
In the case of another known occupant protection device for a motor vehicle having an inflatable airbag in the region in front of an occupant, described in German Gebrauchsmuster No. 297 00 804 the said airbag is unsymmetrically shaped in the inflated state, in such a way that there is a greater volume in the head-impact region that in the thorax-impact region. Reference is generally made to the possibility of subdividing such an airbag into a plurality of chambers to be inflated, although nothing specific is stated in this respect. Here too, an initial gas jet is directed from the gas generator at the occupant with undesired aggressiveness.
Also known is a side-impact occupant protection device for a motor vehicle, described in German Offenlegungsschrift No. 195 38 657, in which an airbag with a thorax-protection gas chamber and a head-protection gas chamber adjoining the latter leaves an exit opening in a backrest. Here, the gas jet from the assigned gas generator is directed in the longitudinal direction of the vehicle, so that in the case of such a side airbag the problem of high aggressiveness due to a gas jet directed at the occupant does not occur.
It is also known to arrange a gas diffuser downstream of a gas generator, as described in International Published Application No. 9625309, with which diffuser the radiating direction of the gas can be influenced and a gas jet directed at an occupant can be divided into different directions. Such a diffuser is an additional component, which requires an installation space and which increases the weight of the vehicle. In most cases such a diffuser cannot be used for an additional function.